Increasing costs of monovinyl-substituted aromatic compound monomers, such as styrene, and reduced availability thereof, have created needs for alternatives to the commercially employed hydrogenated butadiene/styrene block copolymers currently of commercial value.
Needed are polymers which either eliminate the monovinyl aromatic compound, such as styrene, or incorporate much reduced amounts of the styrene, and yet produce highly desirable thermoplastic compositions.
Butadiene/high styrene block copolymers, particularly radial block copolymers, have high green tensile values and elongations at room temperature, but these values tend to be reduced as the test temperatures increase. Needed are block copolymers, employing reduced amounts of copolymerized styrene, yet with improved or increased green tensile values, particularly at elevated temperatures.